Standard Test Method for Measurement of Magnetically Induced Torque on Medical Devices in the Magnetic Resonance Environment

Importancia y uso:

5.1 This test method is one of those required to determine if the presence of a medical device may cause injury in the magnetic resonance environment. Other safety issues which should be addressed include but may not be limited to magnetically induced force (see Test Method F2052), RF heating (see Test Method F2182), and image artifact (see Test Method F2119). ISO TS 10974 addresses hazards produced by active implantable medical devices in the MR environment.

5.2 The terms MR Conditional, MR Safe, and MR Unsafe, together with the corresponding icons in Practice F2503, shall be used to mark the device for safety in the MR environment.

5.3 The acceptance criterion associated with this test shall be justified. If the maximum magnetically induced torque is less than the product of the longest dimension of the medical device and its weight, then the magnetically induced torque is less than the worst-case torque on the device due to gravity. For this condition, it is assumed that any risk imposed by the application of the magnetically induced torque is no greater than any risk imposed by normal daily activity in the Earth's gravitational field. This is conservative. It is possible that greater torques also would not pose a hazard. (For example, device position with respect to adjacent tissue, tissue ingrowth, or other mechanisms may act to prevent device movement or forces produced by a magnetically induced torque that are greater than the torque due to gravity from causing harm to adjacent tissue.)

5.4 This test method alone is not sufficient for determining if an implant is safe in the MR environment.

5.5 The magnetically induced torque considered in this standard is the magneto-static torque due to the interaction of the MRI static magnetic field with the magnetization in the implant. The dynamic torque due to interaction of the static field with eddy currents induced in a rotating device is not addressed in this test method. Currents in lead wires may induce a torque as well.

Subcomité:

F04.15

Referida por:

F2503-23E01, F2503-23E01, F2182-19E02, F2052-21, F3666-25, F2182-19E02, F1831-24, F2052-21, F3160-21, F2119-24, F2182-19E02, F2503-23E01, F3395_F3395M-24, F2052-21

Volúmen:

13.01

Número ICS:

17.220.20 (Measurement of electrical and magnetic quantities)

Palabras clave:

force, magnetic; implant; metals (for surgical implants); MRI (magnetic resonance imaging); MR safety; torque, magnetic;